Solid state light flasher system



Feb. 3, 1970 F. v. EFFENBERGER sOLIusTATE LIGHT FLASHER SYSTEM Filed Sept. 6, 1967 E l 22 T 1477'0R/VEYS' United States Patent 3,493,927 SOLID STATE LIGHT FLASI-IER SYSTEM Frank V. Elfenberger, 403 Newark Ave, Point Pleasant Beach, NJ. 08742 Filed Sept. 6, 1967, Ser. No. 666,560 Int. Cl. 860g 1/38, 1/48 US. Cl. 34083 13 Claims ABSTRACT OF THE DISCLOSURE A solid state circuit used in conjunction with a flasher unit and directional indicating lamps with necessary electrical connections and switching apparatus to provide an emergency flash feature such that the directional lamps may -be selectively connected to automatically flash either synchronously or alternately. An indicator light is provided to provide information regarding proper circuit connection.

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a flasher system of the type utilized on commercial and military road vehicles. In the past, systems of this general type have been limited to the sole feature of providing a directional signal. In a directional signal system, only the lights on one side of the car can flash and simultaneous operation of the indicating lamps on both sides of the vehicle is not possible. Moreover, in order to alternately flash lights on opposite sides of the vehicles, it is necessary to manually control the directional switch which supples power to the directional lamps.

The present invention provides for flexible operation of directional light systems which were previously of limited use. With this invention, directional lamps which are normally provided on left and right sides of vehicles may be operated individually, synchronously, or alternately. The invention provides for a solid state circuit which can be incorporated in any existing directional light flasher system. These existing circuits normally function to supply power to the directional lamps on either side of the vehicle depending on the position of the directional switch. The solid state circuit according to the invention provides for solid state elements which conduct in relation to the position of the abovementioned directional switch and a selector switch which is incorporated in the invention. The position of these switches determines the biasing potential on the various solid state elements such that when power is supplied to flash the directional lights on one side of the vehicle, the directional lights on the other side can be made to flash simultaneously or alternately. The solid state circuit according to the invention also provides for an indicator lamp which will flash, remain steadily on or remain steadily off depending upon the position of the directional switch and the selector switch.

It is therefore an object of the present invention to eliminate the drawbacks of these aforementioned systems.

It is another object of this invention to provide a circuit which permits either synchronous or alternate operation of the directional indicating lamps.

It is still another object of the present invention to provide a solid state circuit in conjunction with a flasher unit and directional lamps so as to permit either alternate or synchronous operation of the directional lamps.

It is yet another object of the invention to provide a solid state circuit of the type described which permits selective operation of the indicator lights in either a synchronous or alternate sequence with an indicator light to indicate proper circuit connection and operation.

A further object of the present invention is to provide a solid state automatic light flasher circuit in conjunction with a flasher, directional switch and at least two banks of lamps with an off and on switch to control power to the circuit, biasing transistor to turn a main transistor on and off in response to the power supplied to the first bank of lamps and the position of the selector switch such that the second bank of lamps can be made to flash alternately or synchronously with the first bank of lamps.

Other objects and advantages will be made obvious to those skilled in the art by the following description when considered in relation to the accompanying drawing of which:

The single figure is a schematic diagram of the flasher circuit according to the invention.

Referring now to the drawing, a source of power, such as the automobile battery, is generally indicated at 12. This source is connected to a conventional bimetallic thermal flasher or other relay having contacts 14 and 16. Connected to the flasher contact 16 is directional switch indicated generally at 18. Switch 18 has switch arm 20 and output switch contacts 22, 24, and 26. Contact 22 is connected to the right-hand bank of directional lamps 29 and 30 via means of conductor 28. Contact 26 is connected to left hand directional lamps 33 and 34 via means of conductor 32. Intermediate contact 24 is the off position of the switch whereby no power is supplied to the directional lamps.

An off/on switch having switch members 38 and 40 which are shown in the oif position is provided for maintaining positive control of power to the remainder of the circuit. A transistor 42 comprising emitter electrode 44, collector electrode 46, and base electrode 48 is connected to intermediate switch 38 and switch 40. The emitter 44 of transistor 42 is connected to source 12 via means of conductor 36 and switch 38. The collector 46 of transistor 42 is connected to ground potential via means of switch 40, conductor 50, conductor 32, and a left-hand bank of lamps such as shown at 33 and 34. The base electrode 48 is connected to ground potential via means of diode 54, indicator lamp 56, and biasing resistor 58. Diode 54 ensures the ability of transistor 74 or 82 to shut off transistor 42. The collector to emitter voltages of transistors 74 or 82 need only drop to a half volt which is the sum of the forward voltage drops of the emitter to base junction of transistor 42 and diode 54 at forward current cutoff. If diode 54 was eliminated, the collector to emitter voltage of transistors 74 or 82 would have to drop to .15 volt or less to shut off transistor 42. A further biasing resistor 52 is connected between emitter 44 and base 48. The function of resistor 52 is to reduce the collector leakage current of transistor 42 to an acceptable value, i.e., that which does not allow the controlled bank of lamps to glow when transistor 42 has its base 48- biased oif. More-over, resistor 52 also prevents thermal run-way in transistor 42. If transistor 42 had a sufliciently low value of collector leakage current and/or if heating of transistor 42 could be kept at a low level as by using a higher power dissipation rating or better heat sinking, it would be possible to eliminate this resistor. The addition of resistor 52, however, is much more economical than any of these methods. As will be explained more fully hereinafter, indicator lamp 56 will flash only when directional switch 18 is in the proper position. It will also turn on and remain on, or on the other hand, remain off, depending on the circuit connections as will be more fully explained hereinafter.

A selector switch 62 is provided for selecting between synchronous and alternate operation of right and lefthand lamp banks 29, 30, 33 and 34, respectively. Selector switch 62 has switch arm 64 and synchronous switch contact 66 and alternate switch contact 68. Switch 62 is con nected to line 28 via means of conductor 60. A PNP transistor 74 is provided having an emitter electrode 76 connected to the emitter 44 of transistor 42, a collector electrode 78 connected to resistor 58 at point 90, and a base electrode 80 connected to synchronous switch contact 66 of selector switch 62 via means of resistor 70. A NPN transistor 82 is provided having a collector electrode 86 connected to emitter 44 of transistor 42, an emitter electrode 84 connected to resistor 58 at point 92, and a base electrode 88 connected through resistor 72 to alternate switch contact 68 of selector switch 62.

In operation, the circuit will operate as a conventional flasher system with switch members 38 and 40 in the off position, as shown in the drawing. Hence, lamps 29 and 30 will intermittently receive power when switch 18 is connected to contact 22 as shown in the drawing. If it is desired to operate directional lamps 33 and 34 in the conventional manner, switch arm 20 is connected to a contact 26. However, if switch arm 20 is positioned as shown, lamps 29 and 30 will intermittently operate in response to the opening and closing of contacts 14 and 16. In order to supply power to lamp 34 when switch arm 20 is in the position shown in the drawing, it is necessary to close ofl/ on switch members 38, 40. The closing of switch member 38 will supply a positive voltage at the emitter 44 of transistor 42. If it is desired to alternately operate right and left lamps 30 and 34, selector switch arm 64 is moved to the alternate contact 68. With the selector switch in this position, a positive voltage will be supplied through line 60, switch 64 and resistor 72 to the base 88 of NPN transistor 82 whenever contacts 14 and 16 of the flasher close supplying power to line 28. The voltage at the base 88 will be slightly less positive than the voltage on collector 86, hence transistor 82 will turn on and current will be caused to flow from the collector to emitter of transistor 82. The turning on of transistor 82 will have a short circuiting or current diverting effect on transistor 42. Transistor 42 will remain oil until such time as contacts 14 and 16 open, thereby removing the potential from the line 28, line 60 and the base of transistor 82 which causes transistor 82 to turn off. When transistor 82 turns off, transistor 42 will be properly biased to turn on, and hence, current will be supplied tolamps 33- and 34 via means of conductors 50 and 32. When flasher contacts 14 and 16 close, lamps 29 and 30 will again receive current via means of line 28, the base 88- of transistor 82 will again receive a positive potential, and the cycle will be repeated.

If it is desired that the lamps 32 and 34 operate synchronously, selector switch arm 64 will be placed in contact with the synchronous position contact 66. When power is supplied to lamps 29 and 30, power will also be supplied to lamp 34 means of conductor 36, switch 38, transistor 42, switch 40, and conductors 50 and 32. Transistor 42 will be properly biased to conduct current in that transistor 74 will be turned off because of the positive potential supplied via means of conductor 60 and re sistor 70 to the base electrode 80. Transistor 74 will remain off until the positive potential is removed from the base 80 by opening of contacts 14 and 16. The opening of contacts 14 and 16 will remove current from lamps 29 and 30, line 60, and base electrode 80 and will cause transistor 74 to be biased on, hence, short circuiting or diverting the current from transistor 42. Transistor 42 will turn off, and hence current supplied to lamp 34 will be removed at the same time as current is removed from lamps 29 and 30, thereby providing for synchronous operation.

Indicator lamp 56 may remain on, flash, or remain off depending on the circuit connections. When directional switch arm 20 is properly connected, indicator lamp 56 will periodically flash. This is the only time that the light will flash, however, as the remainder of the time indicator light either remains steadily on or steadily off. In the position of switch 18 and 62 as shown in the drawing, indicator lamp 56 will only flash when left lamps 33, 34 flash. When power is being supplied to right lamps 29 and 30, transistor 82 will conduct, hence current will be diverted away from lamp 56, and therefore lamp 56 will turn otf. Hence, lamp 56 will alternately turn on and off, or flash as light 29, 30 flash.

If switch arm 20 remains in the position shown, but switch arm 64 is placed in contact with contact 66, indicator lamp 56 will flash whenever both banks of lamps flash. When power is disconnected from lamps 29 and 30, current will flow from base 88 through resistor 72 and transistor 82 will conduct, hence current will be diverted from lamp 56, and hence it will turn ofr". Hence, lamp 56 will alternately flash as both the right and left-hand banks of lamps synchronously flash.

As has 'been indicated above, indicator lamp 56 will flash only if switch 38 is closed and switch 18 is operated in the correct position which is position 22 in the drawing. If switch arm 20 is placed in the incorrect position, such as position 26 in the drawing, lamp 56 will not flash. Assuming that switch 62 is in the position shown in the drawing but that switch arm 20 is connected to contact 26, transistor 82 would be biased off through resistor 72 and lamp bank 29, 30. Although it would not conduct, because of the potential applied to emitter 44 and collector 46, transistor 42 would have its base biased on through diode 54, indicator lamp 56, and bias resistor 58. Thus, a current path from source 12 through resistor 52, diode 54, lamp 56 and resistor 58 will be established which will cause lamp 56 to illuminate steadily.

If, on the other hand, switch arm 20 is connected to contact 26 and switch arm 64 is connected to contact 66, transistor 74 would be biased on by the current through resistor 70, line 60, and lamp bank 29, 30. Thus, transistor 42 would have its base 48 biased oil by the voltage drop across biasing resistor 58 and lamp 56 will not illuminate. The indicator light 56 can be used to rapidly determine the position of switch 62, the operability of lamp 56, and the correctness of directional switch 18.

Although only two directional indicating lights are shown from each bank of lamps, it is appreciated that any number of lights could be connected in parallel or series connection as desired. It should also be noted that leads and may be interchanged such that lead 50 is connected to lamps 29 and 30 and lead 60 is connected to lamps 33 and 34. This interchange will not affect the circuit operation providing directional switch arm 20 is connected to contact 26. As explained above, lamp 56 will flash only when directional switch arm 20 is in the proper position. If leads 50 and 60 are interchanged, lamp 56 will flash when switch arm 20 is connected to contact 26.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

What I claim is:

1. A solid state light flasher circuit comprising:

a first and second bank of directional signal lamps, each bank in series circuit relation with a source of power, a flasher unit which has intermittently operated contacts, and a manually operable direction switch for making and breaking said series circuits;

a first solid state switching means connected in series circuit relation with said source and said second bank of lamps;

a selector switch connected to said first bank of lamps for providing selection between synchronous and alternate operation of said first and second banks of lamps;

a second solid state switching means connected to said first solid state switching means and to said selector switch for providing proper biasing potential to cause said first solid state switching means to become nonconductive when said power source is supplying current to said first bank of lamps and to cause said first solid state switching means to become conductive when said power source is not supplying current to said first bank of lamps; and

a third solid state switching means connected to said first solid state switching means and said selector switch for providing proper biasing potential to permit said first solid state switching means to conduct current when said power source is supplying current to said first bank of lamps and to cause said first solid state switching means to become nonconductive when said power source is not supplying current to said first bank of lamps.

2. The flasher circuit of claim 1 wherein a manually operable switch is connected in series circuit relation with said source, said first solid state switching means, and said second bank of lamps.

3. The flasher circuit according to claim 1 wherein said first and third solid state switching means are transistors of one polarity and said second solid state switching means is a transistor of opposite polarity.

4. The flasher circuit of claim 3 wherein an indicator lamp is connected to the base of said first transistor for indicating when said direction switch is properly connected to said first bank of lamps.

5. A solid state automatic flasher circuit comprising:

a flasher unit;

a directional switch;

first and second banks of lamps;

said flasher unit, directional switch and said first bank of lamps being connected in series circuit relation with a power source;

a first solid state switching means connected in series circuit relation with said source and said second bank of lamps;

a selector switch connected to said first bank of lamps;

a second solid state switching means connected to said first solid state switching means and to said selector switch for providing proper biasing potential to cause said first solid state switching means to become nonconductive when said power source is supplying current to said first bank of lamps and to cause said first solid state switching means to become conductive when said power source is not supplying current to said first bank of lamps; and

a third solid state switching means connected to said first solid state switching means and said selector switch for providing proper biasing potential to permit said first solid state switching means to conduct current when said power source is supplying current to said first bank of lamps and to cause said first solid state switching means to become nonconductive when said power source is not supplying current to said first bank of lamps.

6. A flasher circuit according to claim 5 wherein a manually operable switch is connected in series circuit relation with said first solid state switching means, said power source and said second bank of lamps.

7. A flashing circuit according to claim 5 wherein said first and third solid state switching means are transistors of One polarity and said second solid state switching means is of opposite polarity.

8. A flasher circuit according to claim 7 wherein the collector and emitter of said second transistor are respectively connected to the emitter and base of said first transistor, and the emitter and collector of said third transistor are respectively connected to the emitter and base of said first transistor.

9. The flasher circuit according to claim 8 wherein the bases of said second and third transistors are connected through biasing resistors to said selector switch.

10. The flasher circuit according to claim 9 wherein an indicator light is connected in the base circuit of said first transistor which alternately flashes on and otf to indicate proper circuit connection.

11. A solid state light flasher circuit comprising:

a first and second bank of lamps;

a source of power;

a flasher which has intermittently operated contacts;

connected to said'source a directional switchconnected to said flasher;

a first transistor;

a second transistor;

a third transistor; and

a selector switch,

said first transistor having an emitter electrode connected to said source of power and a collector electrode connected to said second bank of lamps; said second transistor having a collector electrode connected to the emitter of said first transistor, an emitter electrode connected to the base electrode of said first transistor, and a base electrode connected to a first position contact of said selector switch; said third transistor having an emitter electrode connected to the emitter electrode of said first transistor, a collector electrode connected to the base of said first transistor, and a base electrode connected to a second position contact of said selector switch; and said selector switch having a movable switch arm connected to said first bank of lamps such that when said switch arm contacts said first position contact said first and second banks will flash alternately and when said switch arm contacts said second position contact, said first and second banks of lamps will flash in synchronism.

12. A flasher circuit in accordance with claim 11 wherein an indicater lamp is connected in the base circuit of said first transistor for indicating when said directional switch is properly connected.

13. The flasher circuit according to claim 11 including an off and on switch which is connected in series circuit relation with said power source and said first transistor and said second bank of lamps.

References Cited UNITED STATES PATENTS 2,835,880 5/1958 Daws 340*81 3,299,402 1/1967 Schilling 34081 3,325,784 6/1967 Erdelitsch et a1. 340-74 JOHN W. CALDWELL, Primary Examiner K. N. LEIMER, Assistant Examiner US. Cl. X.R. 

